Seal and trommel for a rotary kiln



Oct. 6, 1970 w. s. SWANSON j SEAL AND 'I'ROMMEL FOR A ROTARY KILN s Sheets-Sheet 1 Filed Dec. 20, 1968 )NVENTOR WILLARD 5; bldAMSOlVv ATTORNEY Oct. 6, 1970 w; s. SWANSON 3,532,330

SEAL AND TROMMEL FOR A ROTARY KILN Filed Dec. 20, 1 968 3 Sheets-Sheet 2 nw /v ron WILLARD 5. SWA/VSO/V ATTORNEY mv m mm mm wm FTI'ILI Oct 6, 1970 w, s, SWANSQN 3,532,330

SEAL AND TROMMEL FOR A ROTARY -KILN Filed Dec. 20, 1968 3 Sheets-Sheet 5 ooooooo o0 /76 I22 I66 //6 Q INVENTOR w/ LARD s. SWANSO/V ATTORNEY United States Patent O SEAL AND TROMMEL FOR A ROTARY KILN Willard S. Swanson, Minneapolis, Minn., assignor t the United States of America as represented by the Secretary of the Interior Filed Dec. 20, 1968, Ser. No. 785,540 Int. Cl. F27b 7/00 US. Cl. 263-32 12 Claims ABSTRACT OF THE DISCLOSURE A trommel is secured to the end of a rotary kiln between axially concentric bearing surfaces. A swiveled inlet caps the trommel at the end opposite the kiln. A housing encloses the trommel and terminates at each end with seals riding on the bearing surfaces, achieving a rotary atmospheric seal. A duct joined to the trommel housing provides sealed access to the trommel.

This invention relates to rotary trommels and more particularly to a combined trommel and end seal for providing atmospherically sealed inlet and outlet access to a rotary kiln.

A trommel is a conical or cylindrical perforated sleeve, usually secured to the discharge end of a rotating drum or hopper, as in a rotary kiln. Rotation of the trommel tumbles the product discharged from the kiln, and sized separation occurs through the trommel perforations.

Prior trommels have been constructed with rotary seals between the trommel housing and rotating kiln drum to facilitate atmospheric sealing of the kiln and trommel. Simultaneous input and output, which are desirable where the kiln product is treated at the end discharge area, were accomplished through the trommel housing. In this prior construction, one end of the trommel remained open to provide inlet access to the kiln. The opening had the disadvantage of causing spillage of the kiln product into the trommel housing unless the opening was made restrictively small. An opening small enough to prevent loss interfered with the input to the trommel and with the treatment of the discharging kiln product. Ca'king of the input substance around the opening and degradation of the trommel end wall impeded effective operation of the kiln. Where combustion of a gas was required at the trommel inlet, the restrictive trommel opening interfered with burner action and subjected the trommel end wall to rapid deterioration.

SUMMARY OF THE INVENTION The present invention provides a sealing fixture which may be attached to an end of any type of rotary kiln or drum where more than one atmospherically sealed inlet and outlet is required. The sealing fixture includes a trommel, capped at one end by a swiveled inlet, and secured at the other end to a kiln drum by an adapting plate. Axially concentric circular bearing surfaces are secured between the trommel ends, prolviding races for the sliding support of packing material. A housing encloses the trommel, terminating at each end with spring biased packing seals which ride in sliding pressure contact with the bearing surfaces. A duct sealed to an opening in the side of the trommel housing adjacent to the trommel discharge area provides an outlet from the kiln. The duct is secured against axial rotation with the trommel and restrains the trommel housing from rotation with the trommel and swiveled inlet. Wheels, sliding bearings, or the equivalent are secured to the duct for movement in the direction of the kiln axis to compensate for thermal expansion in the direction of the axis.

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In one embodiment of the invention, perforated arcuate trommel quarter-sections are inserted into a mated supporting framework to form a continuous trommel screen. The trommel sections are interchangeable with sections having perforations of any desired dimension. Individual trommel screens can be used alone or ganged in series to provide progressively graduated kiln discharge in association with a correspondingly partitioned discharge duct. Continuous cylindrical trommel screens alternatively provide added strength where large perforations are required.

Spillage and deterioration at the trommel end are avoided by joining a swiveled inlet directly to the trommel end support for rotation with the trommel. As no obstruction intrudes in the path of the inlet, which in the preferred embodiment is a burner nozzle, efficient operation is insured.

Complete atmospheric isolation of the kiln interior is achieved by attaching the outlet duct to a closed container or, alternatively, by submerging the end of the duct under water. The latter method is particularly advantageous where the kiln product is quenched in a water bath.

Accordingly, it is an object of the present invention to provide sealed inlet and outlet access to a rotary kiln.

It is a further object of this invention to provide a sealed trommel for attachment to a rotary kiln.

It is a still further object of this invention to provide a sealing fixture having bearing surfaces parallel to the axis of trommel rotation.

It is a still further object of this invention to provide a sealing fixture having bearing surfaces perpendicular to the axis of trommel rotation.

It is a still further object of this invention to provide a burner nozzle secured to and rotatable with a sealed trommel and rotary kiln.

It is a still further object of this invention to provide a trommel including a ganged series of trommel screens with perforations of different sizes. I

It is a still further object of this invention to provide a trommel screen including removable trommel sections.

It is a still further object of this invention to provide a trommel housing and outlet duct which are slidably mounted to compensate for kiln expansion.

These and other objects of the invention will become fully apparent with reference to the following specification and drawing which describe the preferred embodiments of the invention.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a side view, partially in section, of one embodiment of a kiln sealing fixture attached to the end flange of a rotary kiln.

FIG. 2 is an exploded view of FIG. 1.

FIG. 3 is an end view of FIG. 1, with a partial interior section.

FIG. 4 is a fragmentary perspective detail of packing and sealing elements of FIG. 1.

FIG. 5 is a sectional side view of another embodiment of a sealing fixture attached to a rotary kiln.

FIG. 6 is an exploded side viewof the sealing fixture shown in FIG. 5.

FIG. 7 is a side vie-w of the sealing fixture shown in FIG. 5, including trommel housing support detail, and

FIG. 8 is an end view of the apparatus shown in FIG. 7.

DESCRIPTION OF THE PREFERRED EMBODIMENT In the figures of the drawing similar reference characters refer to similar parts. Systematically arrayed duplicate parts are shown only in part for the sake of clarity in the drawings.

In FIGS. 1 and 2 a sealing fixture is shown at tached in abutting relationship to the end flange 12 of a rotary kiln 14. Sealing fixture 10 is adaptable to any size or type of rotary kiln or drum, many of which are well known in the prior art. As the specific construction of the kiln is well known and forms no part of the present invention it will not be described in further detail.

A flat centrally apertured disc 16 shaped for close fitting abutment with flange 12 of kiln 14 serves as an adapter plate and facilitates rigid sealed attachment of sealing fixture 10 to the kiln. This attachment and others to be described, may be accomplished by fasteners, such as bolts 2 shown in FIG. 2, or the equivalent. A cylindrical tube 18 is concentrically joined at one end to the outer face of adapter plate 16, and at the other end to a bearing ring 20 at an internal wall 21 of the ring. The peripheral outer surface of bearing ring 20 is machined to provide a smooth bearing surface or race 22. A circular flange 23 extends inward from bearing surface 22 to form a receptacle for cooling fluid in the lower portion of the ring. Refractory material 24 fills the annulus bounded by plate 16, tube 18, and ring 20, forming a continuous central aperture.

Four H-section slotted trommel supports 26, shown in cross-section in FIG. 3, are secured in quadrature to the exterior end wall 19 of bearing ring 20 at one end, and to a flat centrally apertured disc 28 at the other end to form a symmetrical open framework. Triangular braces 30 reinforce the supports at each end. Four arcuate trommel quarter-sections 32 are inserted through the aperture in disc 28 and into the tangentially oriented slots of supports 26, providing a continuous closed trommel screen 33. Radial perforations 34, designed to allow passage of sized particles, are uniformly spaced on the trommel sections 32 to provide a sifting separation of the kiln product. Trommel sections 32 are interchangeable with sections suitably perforated for separation of any size kiln product.

An apertured disc 36, which is similar in shape to disc 28 and has a smaller central aperture, is concentrically secured to disc 28 by suitable fasteners and holds trommel sections 32 in place. A perforated cylindrical trommel screen 38 is secured to disc 36 at one end and to a bearing ring 40 at the other end. Bearing ring 40 is an inverted duplicate of bearing ring 22 and has a similarly machined bearing surface 42. Radial perforations 44, which are uniformly spaced on the surface of screen 38, are analogous to the perforations 34 in screen 33. Large perforation-s 44 are provided in the embodiment shown in FIGS. 1 and 2 to discharge the conglomerate residue r remaining after the initial separation by trommel screen 33. Any number of trommel screens may be ganged in series to perform a progressive graduated separation of the kiln product.

A burner nozzle 46 is secured by a radial flange 48 to the interior end wall 41 of bearing ring 40, with the nozzle facing the end opening of kiln 14. A truncated conical cap 50 and a centrally apertured cu 52 join at flange 48 to form an annulus which is lined with a refractory toroid 54. An end cap 56 is secured in alignment with the aperture in cup 52 and a threaded input pipe 58 is secured to the end cap. Swivel connector 60 is threaded to input pipe 58 to provide rotational freedom between the burner nozzle and input supply pipe (not shown). Thermal expansion of the kiln 14 in the axial direction relative to the supply pipe may be provided by well known Slip fittings, U-joints, or rubber sections (not shown) in the input suply pipe.

A tubular trommel housing 62 encloses trommel screens 33 and 38, terminating at each end adjacent to bearing surfaces 22 and 42 with outwardly extending circular flanges 64 and 66, as shown in FIGS. 1 and 2. An octagonal array of holes 68 extends through flanges 64 and 66 in the axial direction of the trommel housing. Eight eyebolts 76 are secured through the holes on each flange with a nut and washer combination 70. Retaining springs 72, mounted on the seven uppermost eyebolts between a washer and flange, bias the uppermost eyebolts in the direction of flanges 64 and 66.

Four quarter-circular packing retainers 74 of rightangular cross-section surround each bearing surface 22 and 42 adjacent to flanges 64 and 66, as shown in FIG. 3. Right-angular brackets 78, having a hole in one arm, are secured by the other arm at each end of packing retainers 74, and are paired in spaced facing relationship in mid-section of each retainer with their holes in circumferential alignment. Bolts 80 and 82 are secured by a nut and washer through a bracket 78, an eyebolt 76, and another facing bracket. Retainer springs 75, secured on the bolts between a bracket and nut, circumferentially constrict the combined retainers, drawing them against bearing surfaces 22 and 42. Graphited asbestos packing 84, or the equivalent, is contained in the interior annulus of the combined retainers 74 and simultaneously secured against bearing surfaces 22 and 42, and flanges 64 and 66 by the combined tension of springs 72 and 75, as shown in detail in FIG. 4.

A flanged duct 86 is joined in alignment with a similarly shaped opening adjacent to trommel screens 33 and 38 on the lower side of trommel housing 62. A divider 88, secured in duct 86, maintains the separation of the kiln product achieved by trommel screens 33 and 38. A U shaped channel 90, with an opening through duct 86, is secured to flange 92 of the duct. Four wheels 94, mounted on axles 96 through the sides of channel 90, and supported on a rigid base (not shown), enable the trommel housing 62 and duct 86 to be aligned with trommel screens 33 and 38, and with bearing surfaces 22 and 42 in the axial direction of the sealing fixture, while restraining rotation of the housing and duct about the axis. Complete atmospheric sealing is provided by submerging the duct outlet in a tank of water (not shown), or by securing the duct to a closed container (not shown).

Spray nozzles 98, mounted in holes 102 in trommel housing 62, as shown in FIG. 2, are attached to a water supply (not shown) for cooling the interior surfaces of sealing fixture 10. Similar provision (not shown) is made to supply cooling water to the cup-shaped annulus on each bearing ring.

Another embodiment of the invention is shown in FIGS. 58. In this embodiment alternate forms of bearings, trommel housing construction, and expansion adjustment are shown in association with a single screen trommel.

A flat centrally apertured disc 116 is symmetrically joined on one side to one end of a cylindrical tube 118 to form a flanged adapter plate, the other side of disc 116 conforming to the shape of flange 112 on a rotary kiln 114. A bearing ring 120 is concentrically joined to the other end of tube 118 at a machined bearing surface 122 on bearing ring 120. A similarly shaped bearing ring 128, having a machined bearing surface 142 and a larger central aperture than ring 128, is mounted in axially concentric alignment with bearing ring 120 by four trommel section supports 126, and triangular braces 130, as particularly described for the embodiment shown in FIGS. l-4. A second cylindrical tube 136 is secured to ring 120 at the inner edge of bearing surface 122 forming a continuous central aperture. Refractory cylinder 124 fills the annulus bonded by surface 122 and cylinders 118 and 136, adjoining the kiln lining 138, shown generally in FIG. 5.

Four perforated arcuate trommel quarter-sections 132 are inserted in supports 126, and extend through the aperture wall of bearing ring 128, ending flush with hearing surface 142 at one end and abutting bearing ring 120 at the other. Burner nozle 146, which is similar in construction to the nozzle 46 shown in FIG. 1, is concentrically secured to the machined surface 142 of bearing ring 128. Swivel input connection 160, secured to the input end of the nozzle, provides rotational freedom between the burner and input pipe (not shown), as previously described.

A tubular trommel housing 162, with radially extending circular flanges 1-64 and 166 encloses the trommel screen 133, formed of section 132 and braces 126, terminating at each end adjacent to bearing surfaces 122 and 142. Flanged packing retainer rings 176, secured to flanges 164 and 166 of housing 162, cooperate to form a U- shaped internal annulus at each end of the housing. Rings of graphited asbestos packing 184, or the equivalent, extend partially into each U-shaped annulus and ride in conformation with the bearing surfaces 122 and 142. Packing material 184 is radially constrained by housing 162 on the outside, and by packing retainer rings 176 on the inside. The packing material is pressed against hearing surfaces 122 and 142 by the combined action of a circumferential array of springs 172 held by bolts 170 between pressure plates 180 and flanges 176, as shown in FIG. 6. These combined constraints upon packing material 184, in association with the sliding abutment of the packing material at bearing surfaces 122 and 142, form a rotary atmospheric seal between the trommel screen 133 and trommel housing 162.

A tubular duct 186 is joined in alignment with an opening on the lower side of trommel housing 162, adjacent the discharge area of trommel screen 133, as shown in FIGS. 7 and 8. The trommel housing 162 and duct 186 are rigidly secured between matched braces 188. Legs 190 are secured to each brace and extend downward terminating with bearing sleeves 194 aligned parallel to the axis of rotation of the trommel. Each sleeve 194 is semirigidly supported by a shaft 192 and bracket 196 for free sliding movement in the direction of axial alignment, and is constrained by the same shaft from rotation with the trommel and burner. This semirigid support of trommel housing 162 prevents rotation of the housing 162 and duct 186, while compensating for thermal expansion of the kiln and sealing fixture.

It can thus be seen that useful fixtures for achieving sealed input and output for a rotary kiln have been provided.

In adapting the present exemplary disclosure to a particular rotary environment numerous modifications within the scope of the invention will become apparent to those skilled in the art.

For example, equivalent adapter plates may be constructed to conform the sealing fixture to any rotary kiln or drum. Alternate bearing devices can be substituted to provide eflicient operation in toxic or fluid environments. The discharge duct may be located as an inlet above the trommel screen, with the screen used as an input separator. The burner nozzle may be replaced by a fluid spray or other inlet, or alternatively used as an outlet of gaseous or solid material. A series of sectional and continuous trommel screens may be arranged to provide graduated discharge separation.

Other modifications will become apparent to those skilled in the art in the light of the above teachings and within the scope of the appended claims.

What is claimed is:

1 Apparatus providing atmospherically sealed inlet and outlet access for a drum rotatable about a longitudinal axis comprising:

a trommel on the axis of rotation located between axially spaced, concentric bearing surfaces,

means at one end of the trommel for sealing the trommel to an end of the drum,

means joined to the other end of the trommel providing a sealed inlet to the drum,

a housing enclosing the trommel and terminating at each end with seals riding on the spaced bearing surfaces, and

a duct joined to the housing and constrained from rotation with the drum.

2. Apparatus providing atmospherically sealed inlet and outlet access for a rotary kiln comprising:

a pair of bearing rings arranged along an axis in spaced relationship and having axially concentric bearing surfaces,

a trommel secured in abutting relationship between the bearing rings,

a burner nozzle with a swiveled input connection, se-

cured to one of the bearing rings on a side opposite the trommel and projecting along the axis in the direction of the rings,

means secured to the other of the bearing rings in abutting relation on the side opposite the trommel and shaped for concentric abutting attachment to the end of the rotary kiln,

a housing enclosing the trommel and terminating at each end adjacent to the bearing surfaces,

sealing means attached to the ends of the housing for sliding conformation with the bearing surfaces to form an atmospheric seal,

a radial opening in the housing adjacent to the trommel,

a duct communicating with the radial opening in the housing at one end and,

means constraining the duct and housing from rotary motion about the axis.

3. The apparatus as described in claim 1 wherein means are provided for movement of the duct and housing in the direction of the axis to compensate for thermal expansion.

4. The apparatus as described in claim 2 wherein means are provided for movement of the duct and housing in the direction of the axis to compensate for thermal expansion.

5. The apparatus as described in claim 1 wherein the trommel includes a series of individual axially aligned trommel screens.

6. The apparatus as described in claim 2 wherein the trommel includes a series of individual axially aligned trommel screens.

7. The apparatus as described in claim 1 wherein the trommel comprises a trommel screen formed of interchangeable sections.

8. The apparatus as described in claim 2 wherein the trommel comprises a trommel screen formed of interchangable sections.

9. The apparatus as described in claim 1 wherein the bearing surfaces are parallel to the axis.

10. The apparatus as described in claim 2 wherein the bearing surfaces are parallel to the axis.

11. The apparatus as described in claim 1 wherein the bearing surfaces are perpendicular to the axis.

12. The apparatus as described in claim 2 wherein the bearing surfaces are perpendicular to the axis.

References Cited UNITED STATES PATENTS 2,132,709 10/1938 Vanderwerp 263--32 2,841,883 7/1958 Francis 26333X JOHN T. CAMBY, Primary Examiner 

